Anti-D in Pregnancy - For Rh Negative Mothers
Patient Information
Obstetrics Department / Maternity Unit
- Author ID: RS
- Leaflet Ref: Obs 097
- Date Produced: July 2026
- Expiry Date: July 2028
Introduction
If you are Rh-negative, your blood type does not have the “D” antigen. (Antigen is a small marker on the surface of blood cells. People who are “Rh-positive” have the D antigen; people who are “Rh-negative” do not.) During pregnancy, if your baby is Rh-positive, a small amount of your baby’s blood may mix with yours. This can cause your immune system to make antibodies that may affect this or future pregnancies. Anti-D is an injection that prevents this from happening. This patient information leaflet explains what Anti-D is, when it is needed, and when to contact maternity triage.
Aims
- To help you understand why Anti-D is important in pregnancy.
- To explain when Anti-D is required, including after certain events known as sensitising events.
- To support you in recognising when to seek medical advice.
- To help reduce the risk of Rh sensitisation and protect future pregnancies.
Risks
Without Anti-D, your body may produce antibodies if your blood mixes with your baby’s blood. These antibodies can cross the placenta in future pregnancies and may cause Haemolytic Disease of the Newborn (HDN), a condition where the baby’s red blood cells are destroyed. Anti-D significantly reduces this risk.
Benefits
- Protects your current and future pregnancies by preventing antibody formation.
- Reduces the risk of HDN, which can cause anaemia, jaundice or serious complications in newborns.
- Supports safer antenatal care by ensuring timely treatment after sensitising events.
- Helps you understand when to seek help, improving early assessment and treatment.
When is Anti-D needed?
Routine dose
A single Anti-D injection is offered at around 28 weeks of pregnancy.
After birth
- If your baby is Rh-positive, you will need Anti-D within 72 hours of delivery.
- A Kleihauer test may be taken to check how much Anti-D is needed. (A Kleihauer test is a simple blood test taken from the mother to check whether any of the baby’s blood cells have mixed with hers. This helps decide how much Anti-D dose is to be administered)
What is a sensitising event?
A sensitising event is any situation where your blood may mix with your baby’s blood.
Before 12 weeks
- Molar pregnancy - A rare condition where a pregnancy develops abnormally and cannot continue. It needs specialist follow-up (Not required for early miscarriage, threatened miscarriage, termination of pregnancy or ectopic pregnancy)
12–20 weeks
- Vaginal bleeding
- Amniocentesis or Chorionic Villi Sampling - tests where a needle is used to take a sample from the womb
After 20 weeks
- Vaginal bleeding
- Falls or bumps to the abdomen
- Car accidents
- Intrauterine death
- Any procedure where foetal blood mixing may occur
- External cephalic version (ECV) - A procedure where a doctor or midwife gently tries to turn a baby inside the womb from the breech position (bottom-first) to cephalic position (head-down first) by pressing on the abdomen.
When should I contact maternity triage?
Please contact triage immediately if you experience:
- Vaginal bleeding (even spotting)
- A fall or bump to your abdomen
- A car accident
- Reduced foetal movements
- Painful contractions or suspected labour
- Any invasive procedure
Prompt assessment ensures you receive Anti-D if needed
Need help or advice?
Speak to:
Community Midwives
Phone lines are manned daily from 9am - 10 am
If you need help outside these hours, please contact Maternity Triage (available 24/7).
- Community Midwives – Ashton, 0300 707 1518 or 0300 707 1505
- Community Midwives - Daisy Team, 0300 707 2772
- Community Midwives - Leigh Team, 0300 707 1023 or 0300 707 1022
- Community Midwives - Wigan Team, 0300 707 1100 or 0300 707 1102
Antenatal Clinic
- Antenatal Clinic - Thomas Linacre Centre, 0300 707 5778
- Antenatal Clinic - Leigh Infirmary, 0300 707 4242
Hospital based services
- Maternity Triage (available 24/7) - 0300 707 8628
- Delivery Suite - 0300 707 8505
- Maternity Ward - 0300 707 8506